Abstract:
In this thesis, we describe the interplay between superconductivity and magnetism
superconductor in Lithium Iron Selenide Hydroxide (Li1-xFex (OH) Fe1-ySe) was investigated
theoretically. A two-band model Hamiltonian which represents the competing energies in the
system was developed based on the electronic band structure of the system. The developed
model Hamiltonian was solved employing the equation of motion approach of the retarded
Green’s function. Using double time retarded Green`s function and the model Hamiltonian we
obtained expression of superconducting transition temperature (Tc), superconducting order
parameter (
), magnetic transition temperature and magnetic order parameter (
)
mathematically. Numerically data were generated from these relations and plotted for discussion.
Finally, we obtained the phase diagrams of superconducting transition temperature versus
coupling constant, superconducting order parameter versus temperature, and superconducting
transition temperature versus magnetic order parameter and magnetic transition temperature
versus magnetic order parameter. Hence, the combined order parameter phase diagram is clearly
shows the possible coexistence of superconductive and magnetism state in some range of
parameter which is the brood agreement with experimental observation
